1. Field of the Invention
The present invention relates to a method for manufacturing a rigid-flexible multilayer wiring board and a collective board.
2. Description of the Related Art
A rigid-flexible multilayer wiring board is used when various wires are drawn around within a housing of a mobile communication terminal, a digital compact camera, or the like. The “rigid-flexible multilayer wiring board” is a multilayer wiring board which includes a rigid portion and a flexible portion. Each of the rigid portion and the flexible portion is formed so as to include a resin layer. Thus, the rigid-flexible multilayer wiring board is a kind of a resin multilayer board. The flexible portion has higher flexibility than the rigid portion. A chip capacitor, a semiconductor IC element, a connector, and the like are mounted on or included in the rigid portion, and circuit elements such as a ground electrode, a capacitor electrode, and an inductor electrode are included in these components. By bending the flexible portion, various wires are three-dimensionally drawn around within the housing. In view of this requirement, the flexible portion is preferably as thin as possible.
A rigid-flexible multilayer wiring board and its manufacturing method are generally a structure and a manufacturing method as described in Japanese Unexamined Patent Application Publication No. 10-200258. In other words, base materials which are previously formed into predetermined shapes are laminated and press-bonded, thereby producing a rigid-flexible multilayer wiring board which includes a thick rigid portion and a relatively thin flexible portion. In this case, press-bonding is difficult. This is because it is difficult to uniformly apply pressure to a laminate having regions with different thicknesses. For example, if the pressure is too low, press-bonding is insufficient and delamination occurs. On the other hand, if the pressure is too high, a thick portion becomes deformed.
As a countermeasure, for example, a structure and a manufacturing method as described in Japanese Unexamined Patent Application Publication No. 2008-34433 are known. In the manufacturing method, plate-shaped base materials are laminated and press-bonded, and a laser beam is applied to a region which is to be a flexible portion. In the region which is to be the flexible portion, an unnecessary portion is entirely removed by the laser beam, and the region becomes thin, whereby the region becomes the flexible portion. However, in the manufacturing method, since the entire unnecessary portion is removed by the laser beam, this removal operation takes time. In addition, due to the laser beam being reflected by copper foil and incident on an undesired portion, a portion which is to be left in a final product may be damaged.